Typically, a control system mainly constructed with a control device such as a programmable logic controller (hereinafter also abbreviated to “PLC”) controls machines and facilities used in many production sites. Typically, a user operates an information processing device, called a support device, to design and produce a control program executed in the control device. The program that is freely designed and produced by the user is also referred to as a user program. Patent Document 1 discloses an example of a function provided with the support device.
Japanese Unexamined Patent Publication No. 2013-117804 (Patent Document 1) discloses a technology of converting an interlock circuit described in a ladder program used in the PLC into a comma separated values (CSV) file in order to display an operation monitoring interlock circuit. In the technology of Patent Document 1, an input element is extracted from a text-format program of the interlock circuit, pieces of information such as a comment, a variable name, a contact type, and a display position on the interlock screen are specified in each input element, and the screen displaying CSV file constructed with the pieces of information is produced.